Automatic matrix retaining and clamping device



p 1958 SIGRUENWALD 2,853,782

AUTOMATIC MATRIX RETAINING AND CLAMPING DEVICE Filed June 20, 1957 5 I it 29 l3 m t u r\ /|2 a /i; 24 33 INVENTOR, Siegfried Gruenwuld 5, M W F 5 75W United Sttes AUTOMATIC MATRIX RETAINING AND CLAMPING DEVICE Siegfried Gruenwald, Memphis, Tenn.

Application June 20, 1957, Serial No. 666,895 6 Claims. (Cl. 32-63) This invention relates to certain new and useful improvements in means for clamping and retaining matrix strips or ribbons which are particularly adapted for usage by dentists in connection with the setting up of fillings administered to patients teeth.

' There have been numerous previous attempts to provide for instruments or tools for clamping or retaining matrix bands or strips for positioning upon the tooth of a dental patient in order to surround and compress a filling material that may have been inserted in the tooth. Prior attempts to provide instruments for this purpose have resulted in instruments which have required laborious and painstaking time-consuming operation and which have failed satisfactorily to perform the functions desired of them. Thus for example, many devices have heretofore employed screw threaded devices which have required careful fitting and subsequent adjustment of the screw threading, consuming a good deal of time in the accomplishment of the desired purpose. Other devices have required the threading of a pin or rod through alined openings in order to attempt to provide for adjustment of the matrix in position. Such devices as that of the latter category have required a special type of matrix band specially prepared 'for use with the particular instrument. v i p A principal object of the present invention is to provide a new and novel means for clamping and retaining dental matrix for use in conjunction with dental patients.

A further object of the invention is to provide such a device'which may easily and quickly be positioned and adjusted with a minimum of time and effort.

v v A further object of the invention is to provide such a matrix retainer which is substantially automatic, and in which a constant pressure is retained on the matrix in virtue of spring means incorporated in the device.

A further object of the invention is to comprise a matrix clamping and retaining device which comprises a substantially cylindrical housing, a substantially U-shaped block slidably mounted in the housing with an elongated plunger member being fixed to the block, and spring means enclosed in the housing urging the plunger member to move the U-shaped block inwardly of the member, the upwardly open portion of the U-shaped block being adapted to receive the ends of a matrix ribbon.

I A further object of the invention is to provide in such a device, means for simply releasably'locking the plunger in advanced position whereby to position the U-shaped block externally of the housing for the reception of the matrix band; and

A further object of the invention is to generally improve the design, construction and efiiciency of means for clamping and retaining matrix bands.

The means by which the foregoing and other objects of the present invention are accomplished and the manner of their accomplishment will be readily understood from the following specification upon reference to the accompanying drawings, in which:

Fig. 1 is atop plan view of the device of the present invention, shown in adjacency to a fragmentary portion Patented Sept; 30, 1958 tion and other parts being shown in elevation.

Fig. 3 is a view similar to Fig. 2, with the plunger and U-shaped block being shown in advanced position and there locked.

Fig. 4 is a top plan view of the device in the position shown in Fig. 3, and with a matrix band preliminarily positioned in the slot of the U-shaped block.

Fig. 5 is a fragmentary sectional view on an enlarged scale taken as on the line VV of Fig. 2.

Referring now to the drawings in which the various parts are indicated by numerals, the present invention comprises a relatively elongated, substantially cylindrical housing 10 provided at its rear end with an end closure 11. At its opposite front end, housing 10 is provided with a guide member'12 which extends inwardly from the front end of the housing 10 to a point intermediate the length of the housing. Guide member 12 preferably comprises opposite walls 13, 14, which are joined at their inner ends intermediate the length of housing 10 by a bearing head 15. Walls 13, 14 are spaced apart to define a guide channel 16 which is rearwardly open and which ends at head 15. I

End closure 11 is apertured as at 17, and guide member head 15 is apertured as at 18.

Slidably mounted in the apertures 17, 18 is an elongated plunger rod 19 which preferably includes a reduced diameter section 20 joined to an enlarged diameter section 21, with a shoulder 22 being provided at the junction between the sections 26, 21. Aperture 18 is of a diameter adapted to slidably receive the reduced section 20, with shoulder 22 being of a diameter greater than the diameter of aperture 18, so as to serve as a stop limiting extending movement of rod 19 through the aperture 18, and aperture 17 is of a diameter adapted to slidably receive rod section 21.

Intermediate the length of rod section 21 a spring seat disc 23 is rigidly fixed, one end of a compression spring 24 being seated against disc 23, and the opposite end of spring 24 being seated against guide member head 15, with the spring surrounding rod 19 throughout a substan-- tial portion of its length. Rod 19 is provided at one end. with a knob 25 which is preferably button-like and is. knurled for easy control of the rod.

Closely adjacent to knob 25 rod section 21 is provided with a notch 27 which is adapted to lockingly latch upon end closure 11, as best shown in Fig. 3. At its opposite end the distal or freeend of rod section 20 is connected with a substantially U-shaped block 29, block 29 being dimen sioned to be slidably received in the channel 16 provided between guide walls 13, 14. Block 29 is preferably fixed to the distal end of rod section 20 as by the threaded attachment best shown in Fig. 5, one leg of the block having the rodsection secured thereto and with the other leg of the block trailing therebehind. The legs of block 29 define an upwardly open slot 30..

Preferably the trailing leg of block 29 is narrowed as at 31 for the purpose of receiving and providing-for the folding about such trailing leg of lengths of a strip of matrix ribbon 32. It will be observed, as best shown in Fig. 3, that rod 19 is of a length somewhat in excess of the length of housing 10, and it will further be seen that the rod, connected with U-shaped block 29, is shiftable from an advanced position (Fig. 3), in which the rod is fully extended and U-shaped block 29 is projected externally of housing 10, to a retracted position (Fig.2), in which the rod is retracted and the U-shaped block is drawn within the interior of the housing, being guided along'the channel 16;;tormed between guide walls I n the use of the device, it is preliminarily positionedas shown in i .an .d w o .1 .,ad anc d, o pviu spring seat 23-forwardly to eornpre$ spring24 between spring seat ,23and ,guide head 15, which, as best shown in Fig. 3, advances block 29 outwardly ofnhousiug ,10 toa'point in which the U-shaped bloelcin externalq hereof. At this point thenotch 27 has beenmioved into rQglSier with the materialpfendclosure :11, andrrod 1,9,;may be flexed s i ly dow wardly, at hia t o and t appurtenances thereof in :thisadvaneed position. With thedeviee in the position asdescribed, and with -spring 2. comp ss ead u ing th r a on, dith r d an of the block-carried thereby, matrix ribbon 3 2 1nay be positioned in slot 30 of ,U-shaped block .29, as best shown in Fig. 4.

" It .will be'observed that theribbon is positioned inslot 3 of the block '29 with the two free ends 35 of the ribbon being passed through theblock slot and projecting therebeyond'and with the ribbon forming ,a .{rel atively enlarged loop 36. Loop 36 may then be positionedover a se1ected,to oth T having a filling F positioned therein, and when properlypositioned with the loop 36 surround: ing the tooth T and filling F in a loose fashion, rod 19 may be flexed to disengage notch 27 from closure 11, releasing the restraint on therod and permitting spring 24 to expand, movingthe rod 19 through the action of spring 24 on spring seat disc 23 to retract u-shaped block 29 within housing 11 and along the channel 16 between guide walls 13, 14. As the U-shaped blQGk 29 is retracted into the housing under the action of spring 24,;the free ends 35 of the ribbon 32 are moved against the rounded shoulder 33, guiding the block 29 into the channel 16 between walls 13, 14, and eifectivelyfolding the free ends 35 of the matrix ribbon 32 about the undercut rearleg of block 29 to the position best illustrated in Fig. 5.

The portions of loop 36 on the.oppositesideotblock 29Iare guided by wall 14 to fold around the opposite side of the undercut rear leg ofblock- 29, andaceofdingly as the spring-urgedrnovement of block :29 into the 1 channel 16 is continued, tension is drawn upon loop 36, drawing it tightly about tooth T as best ShQWn in Fig.1.

9 It thus will be seen that theloop 3 6,is maintained under a constant spring tension, maintaining so long as desiwd atension upon the loop engaging against the fillingFoftooth T, insuring that thisfilling vwill be properly held in position. When itis desired to release the ribbon 32 from the tool of the presentinvention, it will be seen that rod 19 may be simply advanced relatively to housing to expose -U-shaped block 29 externally of the housing, and thus toprovide for the removal of ribbon 32 from the open slot of ,U-shaped blocl ,29. It will readily be observed that with the tool ,ofthe present invention a matrix may be simply and quickly positioned for the purpose of engaging and holding a f lling in a dental patients tooth, and that ,theeun berem r d a i s eto ore nece s ry th 'de s have heretofore been proposed have been at rh de tali ut eon m y w h t e present oo ha d nddqe notne di ogosto thedifli ultie oh thr adipga devic n orlderto-es ahlish .a tension orra matr t e tension herein ein quickly andli ificiently esta lishe y -the.;:spring:urged operation {Qflfll present device. Ifidesired, :the matrixaband maytheflisconnected from :,-the :tool: :after :the 1 positioning has-ibeen e'fiegteid,

and maybeleft in place untilthefilling has completely set.

It will further be observed that in virtue of the springoperated means of the present invention the matrix loop automatically adjusts itself to any tooth size with which it may be used. It will further be observed that when the U-shaped .block has been retracted into clamping and retaining position, ;it;is :yjrtually impossible to dis engage the matrix band therefrom accidentally ,and the matrix band will ,only be released therefrom upon the subsequent advancement of the rod and U-shaped block to the extended position such gas ;is shown ;in Fig. 3.

I claim:

1. A device forretaining a dental matrix ribbon in use position comprising a housing,,a;plunger reciprocably and slidably mounted in said housing, said plunger extending from rear to front of said housing, a guide member Within the forward end portion of said housing, in- ,elu iug a head intermedia the len h of said housing, and: extending to :the front end ofsaid rhousing,ssai.d;membe: in luding .a sp ced pair of substantially .fl upr ght walls extending from said head to the front end vof said housing and defining a channel, ,said channel being forwardiy open, the forward portion of said plunger-extending through-'said;head into said channel, .a'substa-nli ll y -ShWddblock including a pair of upright legsand an upwardl o en slot between said egs f r receivin amatri -ri bom ne of :sai le being fixedrto that-rpm en ofsa dplung r. nd the other of sai l gs positioned forwardlyv thereof, saidblock being enc;ased; in said :hQllS- iusand snug y and slidab yengag nglsaid channel walls, a spr ng ea m unte n s P n er rearwardly of sai head, asompres on pringhousedwithin said;h.O iug inte posed et en saidseat and said head and-mging said plunger :to -.move said block ,rearwardly ,along saidchannel, said plunger and blockbeing shiftabletto and from an extended position inwhich said block i positioned beyond the front end oflsaid housingto receive the ends of amatrix ribbon from and toaretractedposition inwhich said block is within said channel :with said matrix ends foldably engaged by a channel Mall, and latch means carried by said plunger ;releasably enge-ging said hou ing insa xtend po ion- 2 ,A ,device for retaining a dental ,rnatrix ribhon in use positioncornprising a housing,a plunger reciprocably and sl dab y mounted in said housing, said plunger extending from .r to f ont :of said h using, :a head intermediate the-le gth ofs aid housing, heforward portion; o sai P ung r extending :ztor-wardly hroug s i head, ,a so stantially 1 U shaped block encased =withinsaid housing-a ncluding a;pair of upright legs and an:upwardly open slot-between said legs for receiving a matrix ribbon,ione of said legs being fixed to -,the front end of said plunger and the other of said legs positioned forwardly thereof, a spring' seat mounted on said plunger rearwardly ,of said. head, .a compression spring housed within said housing interposed between said seat and sa -hea an .n in s i plun er to move said block reamardly within said housing, said plunger and block eing .shif abl t an from an exten p ition in which said block is positioned beyond the front 16nd of a ho sin t receivethe ends,- of a. ma rix ribbon from and. to-.;ar rac e positionin which said block is'within aid h u ng, andllat hrmeans. carried by said Plung r releasably engaging said -housingin said extended position.

1 Ardevicerfor re aining a dental matrix ribbon in use positioncomprising-a housing, a P ger reQiP QQah Y and slidably mounted, ;said,housing, said plungcrzex tending from rear ,to -;front of said housing, :a headinterrnediate thewlength -of said housing, the forward :portion of sai'd plunger extending forwardly through said head, :a substantially U-shaped block encased in said housing and including a pair of upright legs-and an up wardlytopen slot-between said'legs-for receiving a matrix ribbon, one of said legs being fixed to the front end of said plunger and the-other of said legs positioned forwardly thereof, a spring seat mounted on said plunger rearwardly of said head, a compressionvspring housed, with said housing interposed between said seat and said head and urging said plunger to move said block rearwardly within said housing, said plunger and block being shiftable to and from an extended position in which said block is positioned beyond the front end of said housing to receive the ends of a matrix ribbon from and to a retracted position in which said block-is within said housing.

4. A device for retaining a dental matrix ribbon in use position comprising a housing, a plunger reciprocably and slidably mounted in said housing, said plunger extending from rear to front of said housing, a guide member within the forward end portion of said housing, including a head intermediate the length of said housing and extending to the front end of said housing, said member including a spaced pair of substantially flat, upright walls extending from said head to the front end of said housing and defining a channel, said channel being forwardly open, the forward portion of said plunger extending through said head into said channel, a substantially U-shaped block including a pair of upright legs and an upwardly open slot between said legs for receiving a matrix ribbon, one of said legs being fixed to the front end of said plunger and the other of said legs positioned forwardly thereof, said block being encased in said housing and snugly and slidably engaging said channel walls, a spring seat mounted on said plunger rearwardly of said head, a compression spring housed wit said housing interposed between said seat and said head and urging said plunger to move said. block rearwardly along said channel, said plunger and block being shiftable to and from an extended position in which said block is positioned beyond the front end of said housing to receive the ends of a matrix ribbon from and to a retracted position in which said block is within said channel with said matrix ends foldably engaged by a channel wall, one of said channel walls and the body of said housing being angularly cut off to provide a portion bevelled relative to the remainder of said device for fitting the gingiva and teeth of a patient.

2,521,467 Lewis 5. A device for retaining a dental matrix ribbon in use position comprising a housing, a plunger reciprocably and slidably mounted in said housing, said plunger extending forwardly from the rear of said housing, a substantially U-shaped block encased in said housing and including a pair of upright legs and an upwardly open slot between said legs for receiving a matrix ribbon, one of said legs being fixedto the plunger and the other of said legs positioned forwardly thereof, spring means urging said plunger to move said block rearwardly within said housing, said plunger and block being shiftable to and from an extended position in which said block is positioned beyond the front end of said housing to receive the ends of a matrix ribbon from and to a retracted position in which said block is within said housing, and latch means carried by said plunger releasably engaging said housing in said extended position.

6. A device for retaining a dental matrix ribbon in use position comprising a housing, a plunger reciprocably and slidably mounted in said housing, said plunger extending forwardly from the rear of said housing, a substantially U-shaped block encased in said housing and including a pair of upright legs and an upwardly open slot between said legs for receiving a matrix ribbon, one of said legs being fixed to the front end of said plunger ,and the other of said legs positioned forwardly thereof,

spring means urging said plunger to move said block rearwardly within said housing, said plunger and block being shiftable to and from an extended position in which said block is positioned beyond the front end of said housing to receive the ends of a matrix ribbon from and to a retracted position in which said block is within said housing.

References Cited in the file of this patent UNITED STATES PATENTS Sept. 5, 1950 FOREIGN PATENTS 879,897 Germany June 18, 1953 forward end of said 

